Wind turbine blades used for horizontal axis wind turbines for generating electrical power from wind can be rather large and may exceed 70 metres in length and 4 metres in width. The blades are typically made from a fibre-reinforced polymer material and comprise an upwind shell part and a downwind shell part.
Often, transporting wind turbine blades from the production facility to the site of wind turbine or the wind turbine power plant requires many transportation steps. Typically, the blades are transported by truck, train or ship and again by truck to the site of the wind power plant. Additionally, reloading between the different types of transportation is needed. Finally, the blades are stored at the production facility and at the site of the wind turbine power plant.
Due to the size and fragility of these large rotor blades, the blades may be damaged during transport as well as during loading and unloading. Such damages may seriously degrade the performance of the blades. Therefore, the blades need to be carefully packaged in order to ensure that they are not damaged.
However, due to the increasing length of modern wind turbine blades, it is gradually becoming more complicated and expensive to transport the blades. It is not uncommon that the transportation costs amount to 20 percent or even higher of the total costs for manufacturing, transporting and mounting the wind turbine blade on the rotor of a wind turbine blade. In addition, some blades are transported to the erection site through different modes of transport, such as by truck, train and ship. Some of these modes of transports may have restrictions on large loads, maximum heights, maximum widths, maximum distances between transport frames or supports, for instance dictated by local regulations. Therefore, there exists a logistic problem of providing transport solutions that are suitable for various types of transport.
Overall, there is a demand for making transport solutions simpler, safer and cheaper. In particular, there is a demand for making such systems more flexible such that adaption to a certain transportation situation is possible. This applies for example for shifting from land transport to sea transport. While height restrictions require lowest possible inter-blade spacings, sea transport may require an increased inter-blade spacing to avoid contact between blades during sea disturbance.
The prior art shows various solutions for transporting more than one rotor blade using a single container or other packaging system, which is an obvious way to reduce the transport costs. However, the afore-mentioned restrictions and limits may increase the difficulty of transporting a plurality of blades using the same packaging system. There is also a need to vary the spatial orientation of blades during transport or prior to transport depending on differences in the dimensions of the blades.
WO 2012/019895 discloses a transportation and storage system for wind turbine blades with a tip end frame assembly and a root end frame assembly. The tip end frame assembly comprises a frame and a tip end receptacle received in the frame. When placed in the tip end receptacle the chord of the blade forms an acute angle with vertical.
WO 2014/064247 describes a transportation and storage system for at least two wind turbine blades. The system is adapted to stack the blades in an alternating root end to tip end arrangement. The tip end of the second wind turbine blade may extend beyond the root end of the first wind turbine blade, and the tip end of the first wind turbine blade may extend beyond the root end of the second wind turbine blade, when the first and the second wind turbine blades are arranged in the packaging system.
WO 2010/125424 A1 discloses an adaptable packing apparatus for aerogenerator blades. The packaging apparatus comprises an external frame and an internal frame. The internal frame is selectively positionable relative to the external frame in at least two positions in order to allow to receive different portions of a blade. The packing apparatus further comprises at least one anchor arm pivotally coupled to the frame and selectively positionable. However, the system requires movable parts and can only provide a single support surface in fixed orientations. Accordingly, the apparatus lacks flexibility in terms of supporting different blade types.
EP 1 813 473 A2 discloses an apparatus for transporting rotor blades. The apparatus comprises a frame with a space to receive a part of the rotor blade. The apparatus further comprises one cushion selectively positionable relative to the frame in at least two different positions. However, the apparatus requires movable parts and can only provide support surfaces in fixed orientations. Accordingly, the apparatus lacks flexibility in terms of supporting different blade types.
While the aforementioned transportation and storage systems are useful for a number of transport situations, there is a need for even more flexible solutions. This applies in particular to the transport of blades of different sizes and having different lengths and chord lengths. Here, prior art systems are found to offer only limited flexibility.
It is therefore a first object of the present invention to provide a transportation and storage system for wind turbine blades which overcomes or ameliorates at least one of the disadvantages of the prior art or which provides a useful alternative.
Particularly, it is an object of the present invention to provide a more flexible transport solution that is able to accommodate for different transport situations and regulatory requirements.
It is another object of the present invention to provide a transport and storage solution that is simple and cost-efficient.